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Frequently Asked Questions

Answers for engineers, contractors and owners, plus our bridge designs, components, kits and capabilities. Search or filter by audience or topic to find what you need.
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For Engineers 18

What is the top of deck to the low-steel dimension?

The top of roadway wearing surface to the low steel elevation varies depending on the span, roadway width and framing configuration. U.S. Bridge has a chart of preliminary floor beam sizes plotted against span (for beam bridges) or roadway width (for truss bridges) that can be used to approximate the structure depth, given certain design parameters. We often work closely with the Owner's engineer during the programming or preliminary design phase to determine a structure depth and substructure loads (reactions), upon request.

What are reactions?

The bridge's supporting loads are called reactions. They are the "reacting" forces from a bridge's own downward gravity force and also from things the bridge carries such as vehicles or pedestrians. Other loads cause corresponding reactions such as those from wind, or streams, or temperature. These are different for each bridge depending on its span, width, truck loading, deck construction and the design code's requirements.

What vehicle loads can be designed for?

Bridge engineers use given loads specified by AASHTO in their published bridge specifications to design bridges. The loads discussed below are specified in the AASHTO Standard Specifications for Highway Bridges, 2002, 17 Edition. They are called "notional" loads as they represent "Hypothetical" trucks. Thus the "H" for the basic two-axle truck, and "HS" for semi-trucks. They based on a statistical analysis of real-world truck traffic. A brief list of some common designations is given below: – H15-44 Truck (2 axles) GVW = 30,000 lbs. – HS15-44 Truck (3 axles) GVW = 54,000 lbs – H20-44 Truck (2 axles) GVW = 40,000 lbs. – HS20-44 Truck (3 axles) GVW = 72,000 lbs The HS25 truck loading is another truck loading specified by many state DOT's to increase their specified loading to accommodate the fact that many trucks on today's highways travel with heavier loads than when the H and HS truck series were determined. This allows for the permitting of more overload permit vehicles on the National Highway System (NHS) and other heavily traveled state system routes. The HS25 is 5/20ths heavier (25% heavier) than the HS20-44 truck. – HS25 Truck (3 axles) GVW = 90,000 lbs. The HL93 truck loading is an updated truck loading found in AASHTO's LRFD Bridge Design Specification, the current edition being No. 6. This truck loading is governed by the larger force effect from one of two loadings: 1) an HS20-44 truck coincident with a newly defined lane load of 0.64 kips/ft.; or 2) a tandem vehicle with two 25k axle loads, coincident with the new lane load. Beyond these commonly specified truck loadings, we routinely design for additional vehicular loads known as Special Design Vehicles. These are, many times, requested by bridge owners with special hauling or access needs such as need in the mining or heavy construction industry. The important thing to know is the vehicle's loaded gross vehicle weight and the corresponding individual axle loads, and the actual axle spacing(s). These are necessary to properly complete the design.

Are there any options other than weathering or painted steel to protect against corrosion?

Hot-Dip Galvanizing is a very popular method to protect against corrosion. It provides inexpensive, long-lasting, superior corrosion protection.

Are the bearings a part of the bridge?

The bearings are usually supplied with the bridge unless excluded within the order. The term "bearings" is more appropriately defined as "bearing device" and usually means everything conveying load between the superstructure and the substructure and includes a "load plate" also known as a "sole plate", a bearing pad made from reinforced elastomers or resins, and a steel "masonry" or "base" plate. For longer truss bridges the load plate is surfaced with polished stainless steel layer and combined with Teflon coating applied to the bearing pad producing a low-friction bearing that allows for slip under thermal expansion and contraction; thus allowing the substructure to be designed for lighter longitudinal forces.

Can the abutments be at differing elevations?

The maximum roadway slope allowed by the roadway designer will govern the bridge slope. Steep slopes are usually accommodated by beveled load plates or special bearings with extra rotational capacity.

Can anchor bolts be set using epoxy resin or must they always be cast in place in the concrete?

The anchor bolts may be embedded into concrete by securing them to the reinforcing of the concrete abutment seat and casting them into the concrete pour or by drilling and anchoring them into the cured concrete using a two-component, non-shrink, non-sag epoxy or methyl methacrylate adhesive, that is moisture insensitive when cured. Nylon or polyester resins are not acceptable.

Is your bridge considered redundant?

Our two-girder through truss bridges are designed in accordance with AASHTO criteria for non-redundant bridges. The bottom chord of a U.S. Bridge truss is a double-element member, using two channels or WT's, which provides internal redundancy to the member. This double member, although no longer recognized as redundant, does provide a robust safety factor with regard to connection deterioration, resistance to overloads, and long-term serviceability. We are in the process of completing a Redundancy Proof Study that we hope will show quantifiable redundancy in alternate load paths such as the floor framing and connections that will allow individual hard-to-inspect members to be declassified as FCM's.

How will your bridge hold up under heavy salting?

Hot-dipped galvanizing is an excellent and proven corrosion protection method. Heavy de-icing chemical application will reduce the overall duration of effectiveness but if proper paving operations and curb and joint details are constructed, any underside deterioration can be kept to a minimum.

How long does galvanizing last?

Galvanizing is a tremendously long-lasting and effective treatment of steel to minimize or eliminate corrosion. U.S. Bridge specifications require that any steel to be galvanized shall be galvanized according to ASTM A123. If done according to this specification and installed properly in a non-industrial environment, the galvanizing protection will last well beyond 100 years (75 years to 1st maintenance, which is defined as 5% rust). It is important to remember that U.S. Bridge's procedure is to fabricate a bridge's components prior to galvanizing. They are then subsequently bolted together into assemblies achieving galvanizing on both sides of a joined piece. This enhances even further, the corrosion protection afforded by galvanizing. Another testament to galvanizing's long term protection is the 35-year Warranty that accompanies this conditioning for primary components of our bridges. According to the American Galvanizers Association, the corrosion rate of zinc is directly influenced by atmospheric conditions. Certain factors that specifically affect the corrosion of zinc include: temperature, humidity, rainfall, sulfur dioxide (pollution) concentration in the air, and air salinity. None of these factors can be singled out as the main contributor to zinc corrosion, but they all play a role in determining the corrosion protection hot-dip galvanized (zinc) coatings can provide in certain environments. When galvanizing is exposed to the natural wet and dry cycles of the atmosphere, it develops a series of zinc byproducts on the surface called the patina. The patina is stable and non-reactive unless exposed to aggressive chlorides or sulfides. The patina is a key component in the longevity of the hot-dip galvanized coating in the atmosphere. For corrosion classification purposes, atmospheres are generally divided into five groups: 1) Industrial Atmospheres; 2) Suburban Atmospheres; 3) Temperate Marine Atmospheres; 4) Tropical Marine Atmospheres; and 5) Rural Atmospheres. Independent and industry testing of galvanized steel samples over decades in industrial, urban, rural, and marine environments, with varying degrees of chlorides, sulfides and other corrosive elements, has yielded performance data for galvanized steel in real world applications.

When is weathering steel not recommended?

Weathering steel should not be used when the low-steel elevation above the water surface is small; less than 10 ft., and the air flow expected under the bridge is poor. This limit is even less, 8 ft., if the stream is flowing. Please check out "A Primer on Weathering Steel (http://www.aisc.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=20278)" by the NSBA/AISC and also "Uncoated Weathering Steel in Structures (http://www.fhwa.dot.gov/bridge/t514022.cfm)" by FHWA.

Are superelevated surfaces a problem?

No. Paving details or finished elevation tables are prepared to account for unique or unusual profiles and superelevated deck surfaces.

Our DOT requires removable forms for concrete deck bridges. How do you address this?

It is one of the deck construction methods that we support and detail for.

What grade of steel is used when designing a bridge?

Typically ASTM A709 Gr. 50 or Gr50W is used. This is an equivalent specification for ASTM A572 Gr50 and ASTM A588 respectively.

What is the horizontal loading for the bridge?

Wind, wind-on-live load, seismic forces, stream loadings and longitudinal (braking) forces all act upon the horizontal (lateral) plane of the bridge and are designed for and accommodated by lateral bracing and/or the deck slab diaphragm.

Can you design and supply the expansion joints?

Our specifications outline numerous expansion joint and joint armor possibilities. We routinely adapt our bridge framing and detailing to accommodate unique or non-typical joint treatments.

Can you cover your vehicular bridges?

Yes. From time to time, this request has been entertained. The combination of steel framing and timber siding and roofing elements can result in an attractive covered bridge structure without the costs of heavy timber framing and the speed of steel construction.

Can you provide a skewed bridge?

We routinely design skewed bridges to fit the bridge to the feature it crosses. This usually involves utilizing a planned skew angle, set by a consulting engineer or the bridge owner for a new project. It many times can involve matching the skew of an existing abutment or pier, using field surveyed information. Variations from the conventional framing arrangements involve steel framing that either align the floor beams with their corresponding truss panel points (these are called skewed floor beams) -or- arrangements that are transverse to the trusses, but on a staggered to an adjacent panel or half panel (this being an orthogonal arrangement).

For Contractors 27

What is the top of deck to the low-steel dimension?

The top of roadway wearing surface to the low steel elevation varies depending on the span, roadway width and framing configuration. U.S. Bridge has a chart of preliminary floor beam sizes plotted against span (for beam bridges) or roadway width (for truss bridges) that can be used to approximate the structure depth, given certain design parameters. We often work closely with the Owner's engineer during the programming or preliminary design phase to determine a structure depth and substructure loads (reactions), upon request.

What are the lead times for drawings and fabrication?

Lead times vary with the particular project and the amount of backlog within our engineering department at that time. Generally speaking, U.S. Bridge can prepare and submit design documentation and engineering plans for a typical beam bridge in 2 weeks, a low (pony) truss bridge in about 4 weeks, and a through truss bridge in about 6 weeks. Additional time will be needed for any of the following complexity factors: 1) Poorly prepared or incomplete scope-of-work 2) Multiple spans of different lengths 3) Vertically curved profile over the bridge 4) Skewed framing 5) Asymmetric railings 6) Supported sidewalks 7) Bridge joint armor and expansion joints 8) Non-Standard Railing Designs 9) SIP formwork 10) Reinforcing for concrete deck slabs

What kind of drawings do we provide?

U.S. Bridge's typical plan set includes a title sheet, design drawings showing framing, truss geometry (if applicable), transverse sections, abutment sections, railing installations, form or plank layout drawings, reinforcing steel plans, anchor bolt layout, field assembly drawings which include lifting weights. These amount to between 8 and 12 drawings. Following the design drawings you will have a bill of material set (approximately 2 to 3 drawings); and shop assembly, and production details (shop drawings which usually amount to another 10 to 25 drawings, depending on complexity). These drawings along with accompanying calculations will be sealed by a professional engineer in the state where the project is located.

Can we provide drawings for a flood or waterway permit?

If a site plan needs to be developed depicting the proposed construction activities and impact limits, a local consulting engineering firm may need to be hired to survey and plan the extent of the project's disturbance. If the Owner would like this task to be completed as part of U.S. Bridge's services, please contact one of our salesmen to explore the possibility with us.

Will you design the foundation?

U.S. Bridge provides professional design and engineering services for the bridge superstructure. Foundations, substructure and approach roadway designs are provided by the owner or owner's representative. If a project needs these design tasks completed as part of a project, U.S. Bridge can contract with consulting engineering firm as a turn-key service. Please contact one of our salesmen to discuss this in more detail.

What lifting points should I plan for to erect the bridge?

Detailed installation manuals are available for contractors or agencies performing the installation. The plans submitted for approval and the plans sent with the bridge at the time of shipment have lifting weights of the field segments and assembled units.

Can our bridge be designed for a stream loading?

Yes. This should be specified in the scope of design tasks or be shown in the contract documents by declaring or depicting water surface elevations above the low steel elevation. Additionally it is important to list the stream velocities to support the force calculations.

How long will it take to splice and set the bridge?

This is highly dependent on the contractor's or agency's experience in handling and assembling steel members. It also is dependent on the bridge's size and complexity. On average for a medium-span, low (pony) truss bridge, an experienced crew of 4, with the proper tools and equipment can unload and assemble the truss girders for erection in two days. They then can set the girders and erect the floor beams on a separate third day. Stringer beams between the floor beams usually take another day. For stringer beam bridges, these can usually be erected in a single day.

How big of crane do I need?

The number of cranes and their lifting capacity is highly dependent on the weight of the heaviest assemblies, the layout of the project site, the staging areas and the proximity of where the crane(s)'s will be set relative to the bridge's position. Proper planning and review of the erection sequence and the rigging operations is crucial to the safety of the workers erecting the bridge. A rigging and erection plan should be prepared by the contractor for review by the Owner's Engineer.

How is the bridge delivered?

The bridge is shipped in pieces called assemblies. They are usually sized to fit on a standard tractor-trailer (53' x 8'-6") and require over-road trucking permits if they exceed these dimensions. Larger span lengths or wider bridge widths will require more truck loads depending on the individual assemblies being shipped. In general though, we can probably best answer this question using as an example, a 120 ft. span by 24 ft. wide, pony truss where the entire bridge will be delivered on 4 to 5 trucks. The truss girders for this bridges will be shipped in field segments and will be stacked in a logical order on their trailers to maximize the trucking load (usually 2 or 3 girder segments per trailer). The floor framing load (floor beams and stringer beams) will follow and are usually shipped on a separate trailer. Bolts are usually shipped early, with the truss segments to expedite their assembly upon unloading. Smaller pieces and miscellaneous items such as lateral bracing, railing, flooring planks or forms are shipped on another truck. Also it is important to remember that the weights for all of the pieces and assemblies are listed in the drawings, and they are physically marked to match the labels given in the plans. This of course assists the contractor in joining the pieces or assemblies together.

How do I repaint the bridge?

After many years of service in harsh conditions, it may be necessary to repaint much or all of your bridge. Depending on your site, it may be beneficial to paint on site using a containment system or it may be more economical to remove the structure and have it shop painted and re-erected. Properly preparing steel surfaces and applying coatings is a technical and complex endeavor. It requires specialized experience, equipment, environmental controls and QC procedures; and involves hazardous materials and equipment. To repaint a bridge in the field, it will likely involve hiring a specialty contractor capable of accessing your site and protecting the environment. They will need to demonstrate their experience painting bridges using the coatings and system you have specified.

Are superelevated surfaces a problem?

No. Paving details or concrete screed tables are prepared to account for unique or unusual profiles and superelevated deck surfaces.

Our DOT requires removable forms for concrete deck bridges. How do you address this?

It is one of the deck construction methods that we support and detail for.

What is the concrete deck and rebar design?

A typical DOT mix design would be for f'c = 4,500 psi and 60 ksi reinforcing steel. A deck slab of 8 in. (min.) is recommended with two layers of reinforcing steel. The depth of slab is defined to be a continuous thickness above the supporting steel including any stay-in-place formwork. The slab reinforcing is usually made up a two layers of #5 and/or #6 bars in each direction, properly lap-spliced where called for and supported by reinforcing "chairs" and tied together, in accordance with state DOT construction specifications. If a specific state's design requirements are to be followed, there are provisions for this in our model specifications.

How do you measure length and width?

Length can be a somewhat ambiguous term when discussing bridges and a more engineering term is "Span". Span is defined by the centerline-of-bearing to centerline-of-bearing distance along the centerline of roadway. Overall length is defined as the total length of the steel members but can sometime mean the open dimension between backwalls. Bridge limits means the distance between approach slabs, if they are proposed, or the distance between the backside of the backwalls, if they are not proposed. Width also can be a very ambiguous term and is better named "Roadway Width" as it explains more about the intended meaning. Roadway width is the clear or open lateral dimension between two rails or two curbs or between a rail and a curb, depending on the edge details. The distance between the centerline of the truss from the rail or curb varies depending on the edge detail and/or the railing attachment method. The dimension between the centerlines of the trusses is the span of the floor beam. The span of the floor beam, like the span of the truss is the dimension used in the structural analysis of the bridge.

Do we supply the anchor bolts?

Yes. For beam bridges they usually are ¾" to 1" diameter and sized to provide 12" to 1'-4" embedment into the concrete abutment seats. For truss bridges they are usually 1 ½" in diameter and sized to provide 1'-6" embedment into the concrete abutment seats. Various material properties, fasteners, and surface requirements are met depending on the Owner's specifications.

Will you have a representative at the site during installation?

Yes. U.S. Bridge will provide on-site technical assistance for the bridge erection, upon request. Co-ordination of schedules is required. Our Project Managers will work with the Owner's representative or contractor to understand the planned schedule and arrive on-site ahead of the lifting operations.

The weight listed is per piece or total?

U.S. Bridge's price quotations list an assumed number for field segments and corresponding preliminary lifting weights, which are subject to change during final design. Lifting weights for individual pieces, assemblies, truss segments and complete truss girders are defined and listed within the drawings to support the contractor's planning. An "as-fabricated" set of plans is shipped with the bridge to assist the contractor during the construction.

What are the foundation requirements?

Repeating from an earlier question, the foundation recommendations should be made by a geotechnical engineer who has obtained soil borings and studied the conditions. The final foundations should be selected and designed by the engineer responsible for the substructure. Abutments support the bridge superstructure by transmitting the bridge's resultant loads, called reactions, through load plates and into bearing pads; and then through masonry or sole plates. These plates spread the load out and into the concrete abutment seat. Anchor bolts are formed or installed into the concrete to prevent the bridge from moving in any unintended directions. We provide professional design and engineering services for the superstructure, but the foundations, substructure and approach roadway designs are provided by the owner or owner's representative. If a foundation and substructure design needs to be prepared, a consulting engineering firm will need to be hired. This can be done through U.S. Bridge as a turn-key service. Please contact your regional salesman to discuss this process.

Are prefabricated bridges simple to install?

Yes. Especially if you have built one before. In many cases, a prefabricated steel vehicular bridge is a faster way to complete a bridge construction project. It depends on many things within the goals of the project and what is specified within the scope of work. It is important to remember that steel bridge construction is a technical enterprise requiring experience in construction methods, crane rigging, steel erection practices, planning, scheduling, and managing resources and manpower. For more information to what's going to be need for your project, please call our Engineering Department to discuss what you are planning – (888) 872-7434.

Are the bearings a part of the bridge?

The bearings are usually supplied with the bridge unless excluded within the order. The term "bearings" is more appropriately defined as "bearing device" and usually means everything conveying load between the superstructure and the substructure and includes a "load plate" also known as a "sole plate", a bearing pad made from reinforced elastomers or resins, and a steel "masonry" or "base" plate. For longer truss bridges the load plate is surfaced with polished stainless steel layer and combined with Teflon coating applied to the bearing pad producing a low-friction bearing that allows for slip under thermal expansion and contraction; thus allowing the substructure to be designed for lighter longitudinal forces.

Can the abutments be at differing elevations?

The maximum roadway slope allowed by the roadway designer will govern the bridge slope. Steep slopes are usually accommodated by beveled load plates or special bearings with extra rotational capacity.

Can anchor bolts be set using epoxy resin or must they always be cast in place in the concrete?

The anchor bolts may be embedded into concrete by securing them to the reinforcing of the concrete abutment seat and casting them into the concrete pour or by drilling and anchoring them into the cured concrete using a two-component, non-shrink, non-sag epoxy or methyl methacrylate adhesive, that is moisture insensitive when cured. Nylon or polyester resins are not acceptable.

Can you design and supply the expansion joints?

Our specifications outline numerous expansion joint and joint armor possibilities. We routinely adapt our bridge framing and detailing to accommodate unique or non-typical joint treatments.

Is any field painting required for a painted bridge?

Yes. Many of the bridge components will be preassembled and completely painted but where bolted field connections are to be made by the contractor, there will be field painting of the coating layers beyond the prime coat. This is because mated pieces in a bolted joint are considered faying surfaces upon which a certain frictional coefficient has been assumed during design. If these surfaces were painted, the joint's design will likely be invalid. Our shop prepares the pieces with a stepped back masking of the coating layers. The construction plans and shop drawings detail the portions of the pieces that are masked off and also depict what will need field painting. The contractor should plan for field painting of these connection areas for a painted bridge.

Is touch-up painting different than field painting?

Yes. Touch-up painting is usually surface painting that is required to repair, scuffs, wear marks or evidence of concrete or construction debris. Deep scratches may require touch-up to more than one layer. The contractor is required to complete touch-up painting on all elements identified by the project engineer and must meet their approval.

How do the paints/protective coatings available today differ from those used in the past?

Protecting exposed structural steel with paint coatings has always been an area of industrial research and scientific advancement. Certainly changes in surface preparation, primer coat content (zinc vs. red lead), application equipment and testing methods have all advanced over the years but much, much more has gone on into the improvements in this industry than can be explained here. To read more about this topic and for a better overall understanding, we suggest reading Chapter 23 of Steel Bridge Design Handbook (http://www.aisc.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=20230), by the NSBA/AISC or Section II of "Designing with Structural Steel, A Guide for Architects, 2nd Edition (http://www.aisc.org/uploadedFiles/Steel_Solutions_Center/Conceptual/My_Project/Files/ArchitectsGuide.pdf)", AISC.

For Owners 37

What vehicle loads can be designed for?

Bridge engineers use given loads specified by AASHTO in their published bridge specifications to design bridges. The loads discussed below are specified in the AASHTO Standard Specifications for Highway Bridges, 2002, 17 Edition. They are called "notional" loads as they represent "Hypothetical" trucks. Thus the "H" for the basic two-axle truck, and "HS" for semi-trucks. They based on a statistical analysis of real-world truck traffic. A brief list of some common designations is given below: – H15-44 Truck (2 axles) GVW = 30,000 lbs. – HS15-44 Truck (3 axles) GVW = 54,000 lbs – H20-44 Truck (2 axles) GVW = 40,000 lbs. – HS20-44 Truck (3 axles) GVW = 72,000 lbs The HS25 truck loading is another truck loading specified by many state DOT's to increase their specified loading to accommodate the fact that many trucks on today's highways travel with heavier loads than when the H and HS truck series were determined. This allows for the permitting of more overload permit vehicles on the National Highway System (NHS) and other heavily traveled state system routes. The HS25 is 5/20ths heavier (25% heavier) than the HS20-44 truck. – HS25 Truck (3 axles) GVW = 90,000 lbs. The HL93 truck loading is an updated truck loading found in AASHTO's LRFD Bridge Design Specification, the current edition being No. 6. This truck loading is governed by the larger force effect from one of two loadings: 1) an HS20-44 truck coincident with a newly defined lane load of 0.64 kips/ft.; or 2) a tandem vehicle with two 25k axle loads, coincident with the new lane load. Beyond these commonly specified truck loadings, we routinely design for additional vehicular loads known as Special Design Vehicles. These are, many times, requested by bridge owners with special hauling or access needs such as need in the mining or heavy construction industry. The important thing to know is the vehicle's loaded gross vehicle weight and the corresponding individual axle loads, and the actual axle spacing(s). These are necessary to properly complete the design.

What codes do you use?

The Standard Specifications for Highway Bridges, 2002, 17th Edition, or the LRFD Bridge Design Specification, 2010, 6th Edition are currently the latest published codes by AASHTO and are what we expect to use for new projects unless otherwise specified. Canadian and European Bridge Design Codes can be used when applicable. 1) Poorly prepared or incomplete scope-of-work 2) Multiple spans of different lengths 3) Vertically curved profile over the bridge 4) Skewed framing 5) Asymmetric railings 6) Supported sidewalks 7) Bridge joint armor and expansion joints 8) Non-Standard Railing Designs 9) SIP formwork 10) Reinforcing for concrete deck slabs

What will the bridge need for abutments?

Bridges generally sit on concrete abutments supported by shallow or deep foundations depending on the subsurface conditions found at the site. Foundation recommendations should be made by a geotechnical engineer who has obtained soil borings and studied the conditions. The final foundations should be selected and designed by the engineer responsible for the substructure. Abutments support the bridge superstructure by transmitting the bridge's resultant loads, called reactions, through load plates, into bearing pads; and then through masonry plates also known as sole plates. These plates spread the load out and into the concrete abutment seat. Anchor bolts are formed into the concrete or installed via drilling and epoxy resin, to generally anchor the bridge to the abutment. This prevents the bridge from moving in any unintended directions. These drawings along with accompanying calculations will be sealed by a professional engineer in the state where the project is located.

What is the lifespan of a bridge?

Bridges are usually designed with an intended design life. This is commonly thought of as 75 years from when the bridge is commissioned into service. The Owner may request a longer design life depending on the function, importance, or sensitivity of the roadway facility; and the bridge's location. This design life period can include many maintenance tasks and repair/rehabilitation projects that will be needed to maintain its performance level and diminish the effects of environmental deterioration. Read a good resource for bridge owners and maintenance. (http://www.fhwa.dot.gov/bridge/preservation/guide/guide.pdf)

Do your bridges meet ADA?

If requested as part of the scope of work, a bridge's pedestrian sidewalk can be designed to meet the requirements of the Americans with Disabilities Act (ADA). Several items to keep in mind include: 1. Profile grades of less than 1:20 (5%) are not governed by Section 4.8.2 of the ADA. 2. Profile grades between 1:20 (5%) and 1:12 (8.33%) are permitted ramps but must have a level landing every 30 ft. (ADA 4.8.4) and must also have an ADA approved hand rail with ADA ("loop") returns (ADA 4.8.5). 3. Bridges must have a toe plate to keep the small wheel of a wheelchair from going off the edge of the deck (ADA 4.8.7). 4. Bridges must have a deck surface that meets the ADA for minimum opening size (ADA 4.5.4).

What are the lead times for drawings and fabrication?

Lead times vary with the particular project and the amount of backlog within our engineering department at that time. Generally speaking, U.S. Bridge can prepare and submit design documentation and engineering plans for a typical beam bridge in 2 weeks, a low (pony) truss bridge in about 4 weeks, and a through truss bridge in about 6 weeks. Additional time will be needed for any of the following complexity factors: 1. Poorly prepared or incomplete scope-of-work 2. Multiple spans of different lengths 3. Vertically curved profile over the bridge 4. Skewed framing 5. Asymmetric railings 6. Supported sidewalks 7. Bridge joint armor and expansion joints 8. Non-Standard Railing Designs 9. SIP formwork 10. Reinforcing for concrete deck slabs

What colors do the bridges come in?

The top coat of any of our paint system can be custom tinted to almost any color that is desired. We will begin by coordinating a color for the bridge using a color chart published by the FHWA for bridge painting in accordance with Federal Standard 595a. An online version of this color chart is available at: http://www.colorserver.net (http://www.colorserver.net/)

What safety rail styles do you offer?

There are two items for consideration when specifying a railing system: the anchoring connection, and the railing members themselves. The following railing options are able to be specified within our specifications: 1. Concrete Safety Shaped Parapet 2. Concrete Curb Mounted Post & Rail 3. Concrete Slab Top-Mounted Post & Rail 4. Concrete Slab Side-Mounted Post & Rail 5. Truss-Mounted Single W-Beam Guardrail with Tube Backup 6. Truss-Mounted Thrie-Beam Guardrail with Tube Backup 7. Stringer Supported Post & Rail 8. Stringer Supported Post & Rail with Tube Backup 9. Stringer Supported Twin Steel Tubular Rail 10. Timber Railing Crash Tested Railing Systems meeting FHWA's MASH Standards are part of the rails listed above. DOT standard railing systems are routinely accommodated. If a system is non-standard, the design may be shown to be acceptable through an equivalency calculation using direction given in the AASHTO specifications. This should be specified in the scope of design tasks. For timber railing, rough sawn timber rails or laminated timber rails may be specified with or without an additional steel back up plate. Also pedestrian rails can be specified using many different assemblies but usually have a top hand rail and a lower rub rail as well as horizontal or vertical pickets. The pickets must be spaced such that a 6" sphere cannot pass between them. Decorative rails can be accommodated for an aesthetic treatment. For more information, see our Railings page (https://usb.energyhill.dev/railing)

Can our bridge be designed for a stream loading?

Yes. This should be specified in the scope of design tasks or be shown in the contract documents by declaring or depicting water surface elevations above the low steel elevation. Additionally it is important to list the stream velocities to support the force calculations.

Will the weathering steel finish stain clothing?

Yes and no. A mild "yes" because it possibly could, if left in contact for a long period of time in a wet weather environment, but practically speaking, "no", not from incidental contact. Generally, it is prudent to paint any railings that pedestrians will come into contact with. This can be accommodated in the specification section under railings. In general though, we can probably best answer this question using as an example, a 120 ft. span by 24 ft. wide, pony truss where the entire bridge will be delivered on 4 to 5 trucks. The truss girders for this bridges will be shipped in field segments and will be stacked in a logical order on their trailers to maximize the trucking load (usually 2 or 3 girder segments per trailer). The floor framing load (floor beams and stringer beams) will follow and are usually shipped on a separate trailer. Bolts are usually shipped early, with the truss segments to expedite their assembly upon unloading. Smaller pieces and miscellaneous items such as lateral bracing, railing, flooring planks or forms are shipped on another truck. Also it is important to remember that the weights for all of the pieces and assemblies are listed in the drawings, and they are physically marked to match the labels given in the plans. This of course assists the contractor in joining the pieces or assemblies together.

What are the costs and benefits of the different paint and coating options?

In order of increasing costs and corrosion protection: 1. Weathering Steel 2. Hot Dip Galvanizing (HDG) 3. 3-Coat Paint System (Zinc-Epoxy-Urethane) 4. 2-Coat Paint System over HDG (Epoxy-Urethane) 5. Thermal Spray Metalizing

What are the span ranges and roadway widths that you cover?

Typically we design stringer beam bridges with spans between 20 ft. and 75 ft. with no real width limitation. Low (pony) truss bridges range between 60 ft. and 200 ft. depending on the roadway's width. Generally they are limited to 3 lanes of width (44 ft. max.) for traffic but may include sidewalks. High (through) truss bridges range between 160 ft. to 300 ft. depending on the roadway's width. Through trusses maybe one, two or three lanes but are dependent on other factors such as skew, live loads, sidewalks and floor construction. For a better understanding of bridge spans and widths, please see our Span/Width Matrix (https://usb.energyhill.dev/downloads/tool_downloads/USB%20Style-Lane-Span%20Comprehensive%20Limits%20v071913.pdf).

Can we provide drawings for a flood or waterway permit?

If a site plan needs to be developed depicting the proposed construction activities and impact limits, a local consulting engineering firm may need to be hired to survey and plan the extent of the project's disturbance. If the Owner would like this task to be completed as part of U.S. Bridge's services, please contact one of our salesmen to explore the possibility with us.

Is the paint job guaranteed?

Yes, as part of our Bridge & Product Warranty, we warrant to the Owner, against defects in material or workmanship for up to 10 years. Contact us to review the full contents of this 10-Year Warranty – (888) 872-7434.

How long will your bridge last?

Generally we design to a design life of 75 years which is consistent with many agency life-cycle protocols. It is within the owner's prerogative to define this differently, at their preference. To understand this a little further, a 75-year design life is the duration of service expected from the bridge's superstructure before its complete replacement. Substructures and foundations are expected to last well over 100 years. The costs to maintain the bridge superstructure over this period are called life-cycles costs and include all the inspection, repair and rehabilitation project costs to maintain the bridge is fair condition. A good resource for bridge owners, with regard to maintenance is: http://www.fhwa.dot.gov/bridge/preservation/guide/guide.pdf

What must I do to maintain new bridge?

There are maintenance tasks and "projects" that can be undertaken to extend the durability of the bridge and prevent premature deterioration. These are many times, site or location specific and would require a long listing of possible suggestions. Your state DOT may a have a bridge maintenance section within their office that has work item suggestions, or they may be able to meet with you to give you opinions about good maintenance practices. U.S. Bridge also is available to meet and go over possible work items. Also a good resource for bridge owners, with regard to maintenance is: http://www.fhwa.dot.gov/bridge/preservation/guide/guide.pdf

Does weathering steel stain?

Protection from staining is recommended and can be accomplished by any of these three methods: 1. Sealing nearby concrete surfaces with an epoxy-urethane coating. 2. Painting the weathering steel in the areas above the respective concrete supports (many times this is the 1st ten feet of the span). 3. Special details for drip bars and drip pans.

Can you cover your vehicular bridges?

Yes. From time to time, this request has been entertained. The combination of steel framing and timber siding and roofing elements can result in an attractive covered bridge structure without the costs of heavy timber framing and the speed of steel construction.

How long will a painted bridge last before re-painting is required?

From AISI's Myths & Realities of Steel Bridges Publication … "There are cost-effective ways of repainting existing bridges. For new construction, there are modern high-performance coatings which comply with EPA standards and which can provide a minimum service life of 25 years prior to first paint maintenance."

How do you measure length and width?

Length can be a somewhat ambiguous term when discussing bridges and a more engineering term is "Span". Span is defined by the centerline-of-bearing to centerline-of-bearing distance along the centerline of roadway. Overall length is defined as the total length of the steel members but can sometime mean the open dimension between backwalls. Bridge limits means the distance between approach slabs, if they are proposed, or the distance between the backside of the backwalls, if they are not proposed. Width also can be a very ambiguous term and is better named "Roadway Width" as it explains more about the intended meaning. Roadway width is the clear or open lateral dimension between two rails or two curbs or between a rail and a curb, depending on the edge details. The distance between the centerline of the truss from the rail or curb varies depending on the edge detail and/or the railing attachment method. The dimension between the centerlines of the trusses is the span of the floor beam. The span of the floor beam, like the span of the truss is the dimension used in the structural analysis of the bridge.

Can you design to meet my state's DOT requirements?

Yes we can. The scope of your project is dependent on knowing whether your State's DOT is participating in the funding of the project or not, and whether following their design guidance or their detail standards will be mandatory. If it is, we will want to know what items are important to the DOT and review those requirements before beginning the preliminary design of your bridge. It will be very important to document this early on in the correspondence and also in the scope of work put forth in your project's proposal and specifications. This will allow for proper planning of submittals, steel procurement and shop inspections to be performed. This will help to more accurately plan approval and delivery dates.

Do your bridges meet AASHTO requirements?

Yes. We design for the specified loads, analysis methods, limit states and design criteria given by AASHTO in their published bridge specifications. The two governing specifications at this time are AASHTO's Standard Specifications for Highway Bridges, 2002, 17 Edition and the AASHTO's LRFD Bridge Design Specification, the current edition being No. 6.

Will you design the foundation?

U.S. Bridge provides professional design and engineering services for the bridge superstructure. Foundations, substructure and approach roadway designs are provided by the owner or owner's representative. If a project needs these design tasks completed as part of a project, U.S. Bridge can contract with consulting engineering firm as a turn-key service. Please contact one of our salesmen to discuss this in more detail.

What lifting points should I plan for to erect the bridge?

Detailed installation manuals are available for contractors or agencies performing the installation. The plans submitted for approval and the plans sent with the bridge at the time of shipment have lifting weights of the field segments and assembled units.

Will you have a representative at the site during installation?

Yes. U.S. Bridge will provide on-site technical assistance for the bridge erection, upon request. Co-ordination of schedules is required. Our Project Managers will work with the Owner's representative or contractor to understand the planned schedule and arrive on-site ahead of the lifting operations.

What kinds of projects are prefabricated bridges best suited for?

A prefabricated truss bridge in many cases is the optimal solution for solving challenging bridge replacements over streams and railroads on low volume roads, especially with clear spans of between 120 ft. to 250 ft. It does this by minimizing the profile grade impacts, the number of substructures needed and the crane costs, as compared to multi-span and long-span prestressed girder options.

What are the most common bridge styles?

U.S. Bridge's Cambridge and Cambridge Flat are the most common vehicular truss bridge styles.

Are there any options other than weathering or painted steel to protect against corrosion?

Hot-Dip Galvanizing is a very popular method to protect against corrosion. It provides inexpensive, long-lasting, superior corrosion protection.

What is the difference between AISC and AASHTO?

AISC stands for the American Institute of Steel Construction. AASHTO is the American Association of State Highway Transportation Officials. AASHTO governs the design of bridges, whether they are wood, steel or concrete. AISC governs the design of steel structures, although most bridges fall outside of AISC's application because most bridges are funded or specified by a government agency. AISC performs and maintains much of the underlying technical history, research and basis for AASHTO's steel design code but the AASHTO Code and its technical subcommittees have supplemented this base with their own history and research.

What are the foundation requirements?

Repeating from an earlier question, the foundation recommendations should be made by a geotechnical engineer who has obtained soil borings and studied the conditions. The final foundations should be selected and designed by the engineer responsible for the substructure. Abutments support the bridge superstructure by transmitting the bridge's resultant loads, called reactions, through load plates and into bearing pads; and then through masonry or sole plates. These plates spread the load out and into the concrete abutment seat. Anchor bolts are formed or installed into the concrete to prevent the bridge from moving in any unintended directions. We provide professional design and engineering services for the superstructure, but the foundations, substructure and approach roadway designs are provided by the owner or owner's representative. If a foundation and substructure design needs to be prepared, a consulting engineering firm will need to be hired. This can be done through U.S. Bridge as a turn-key service. Please contact your regional salesman to discuss this process.

Are prefabricated bridges simple to install?

Yes. Especially if you have built one before. In many cases, a prefabricated steel vehicular bridge is a faster way to complete a bridge construction project. It depends on many things within the goals of the project and what is specified within the scope of work. It is important to remember that steel bridge construction is a technical enterprise requiring experience in construction methods, crane rigging, steel erection practices, planning, scheduling, and managing resources and manpower. For more information to what's going to be need for your project, please call our Engineering Department to discuss what you are planning – (888) 872-7434. To read more about this topic and for a better overall understanding, we suggest reading Chapter 23 of Steel Bridge Design Handbook (http://www.aisc.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=20230), by the NSBA/AISC or Section II of "Designing with Structural Steel, A Guide for Architects, 2nd Edition (http://www.aisc.org/uploadedFiles/Steel_Solutions_Center/Conceptual/My_Project/Files/ArchitectsGuide.pdf)", AISC.

How will your bridge hold up under heavy salting?

Hot-dipped galvanizing is an excellent and proven corrosion protection method. Heavy de-icing chemical application will reduce the overall duration of effectiveness but if proper paving operations and curb and joint details are constructed, any underside deterioration can be kept to a minimum.

How do I repaint the bridge?

After many years of service in harsh conditions, it may be necessary to repaint much or all of your bridge. Depending on your site, it may be beneficial to paint on site using a containment system or it may be more economical to remove the structure and have it shop painted and re-erected. Properly preparing steel surfaces and applying coatings is a technical and complex endeavor. It requires specialized experience, equipment, environmental controls and QC procedures; and involves hazardous materials and equipment. To repaint a bridge in the field, it will likely involve hiring a specialty contractor capable of accessing your site and protecting the environment. They will need to demonstrate their experience painting bridges using the coatings and system you have specified.

How long does galvanizing last?

Galvanizing is a tremendously long-lasting and effective treatment of steel to minimize or eliminate corrosion. U.S. Bridge specifications require that any steel to be galvanized shall be galvanized according to ASTM A123. If done according to this specification and installed properly in a non-industrial environment, the galvanizing protection will last well beyond 100 years (75 years to 1st maintenance, which is defined as 5% rust). It is important to remember that U.S. Bridge's procedure is to fabricate a bridge's components prior to galvanizing. They are then subsequently bolted together into assemblies achieving galvanizing on both sides of a joined piece. This enhances even further, the corrosion protection afforded by galvanizing. Another testament to galvanizing's long term protection is the 35-year Warranty that accompanies this conditioning for primary components of our bridges. According to the American Galvanizers Association, the corrosion rate of zinc is directly influenced by atmospheric conditions. Certain factors that specifically affect the corrosion of zinc include: temperature, humidity, rainfall, sulfur dioxide (pollution) concentration in the air, and air salinity. None of these factors can be singled out as the main contributor to zinc corrosion, but they all play a role in determining the corrosion protection hot-dip galvanized (zinc) coatings can provide in certain environments. When galvanizing is exposed to the natural wet and dry cycles of the atmosphere, it develops a series of zinc byproducts on the surface called the patina. The patina is stable and non-reactive unless exposed to aggressive chlorides or sulfides. The patina is a key component in the longevity of the hot-dip galvanized coating in the atmosphere. For corrosion classification purposes, atmospheres are generally divided into five groups: 1. Industrial Atmospheres; 2. Suburban Atmospheres; 3. Temperate Marine Atmospheres; 4. Tropical Marine Atmospheres; 5. Rural Atmospheres. Independent and industry testing of galvanized steel samples over decades in industrial, urban, rural, and marine environments, with varying degrees of chlorides, sulfides and other corrosive elements, has yielded performance data for galvanized steel in real world applications. For results, view the "Time to First Maintenance" chart (link below). http://www.galvanizeit.org/images/uploads/publicationPDFs/Galvanized_Steel_Time_to_First_Maintenance.pdf

When is weathering steel not recommended?

Weathering steel should not be used when the low-steel elevation above the water surface is small; less than 10 ft., and the air flow expected under the bridge is poor. This limit is even less, 8 ft., if the stream is flowing. Please check out "A Primer on Weathering Steel (http://www.aisc.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=20278)" by the NSBA/AISC and also "Uncoated Weathering Steel in Structures (http://www.fhwa.dot.gov/bridge/t514022.cfm)" by FHWA

Will the weathering steel dripping in the creek be an environmental issue?

Corrosion of weathering steel is no different than many other naturally occurring oxidation or weathering processes and is a common occurrence in nature, whether it is naturally occurring elements or man-made materials. To read more about weathering steel, please check out "A Primer on Weathering Steel (http://www.aisc.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=20278)" by the NSBA/AISC and "Uncoated Weathering Steel in Structures (http://www.fhwa.dot.gov/bridge/t514022.cfm)" by FHWA.

How do the paints/protective coatings available today differ from those used in the past?

Protecting exposed structural steel with paint coatings has always been an area of industrial research and scientific advancement. Certainly changes in surface preparation, primer coat content (zinc vs. red lead), application equipment and testing methods have all advanced over the years but much, much more has gone on into the improvements in this industry than can be explained here. To read more about this topic and for a better overall understanding, we suggest reading Chapter 23 of "Steel Bridge Design Handbook (http://www.aisc.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=20230)", by the NSBA/AISC or Section II of "Designing with Structural Steel, A Guide for Architects, 2nd Edition (http://www.aisc.org/uploadedFiles/Steel_Solutions_Center/Conceptual/My_Project/Files/ArchitectsGuide.pdf)", AISC.

Bridge Designs 68

What type of bridge is the U.S. Bridge Cambridge?

The Cambridge is a Warren truss with a polygonal (camelback) top chord, engineered for rural and industrial vehicular crossings.

How is the Cambridge bridge fabricated?

The Cambridge is fabricated by U.S. Bridge in Cambridge, Ohio as an AISC-certified Advanced Steel Bridge Fabricator. It uses all-bolted, CNC-drilled connections, so no field welding is required during installation.

What is the Cambridge bridge best used for?

The Cambridge is best suited for rural and industrial vehicular crossings. Common applications include county and municipal road crossings, rural highway spans, industrial site access.

Where is the Cambridge commonly installed?

The Cambridge is installed for projects such as county and municipal road crossings, rural highway spans, industrial site access, and other crossings that match its span range and loading.

What span lengths can the Cambridge cover?

A typical Cambridge covers about 60–250 ft. Every bridge is custom-engineered to the site, so the exact span, width, skew and loading are confirmed during design.

Is the Cambridge AASHTO compliant?

Yes. The Cambridge is designed to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer.

What finishes are available for the Cambridge?

The Cambridge is offered in weathering steel or hot-dip galvanized steel, with optional shop-applied paint systems for added durability and custom color.

How is the Cambridge delivered and installed?

The Cambridge is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What type of bridge is the U.S. Bridge Cambridge Flat?

The Cambridge Flat is a Warren truss with a parallel (flat) top chord, engineered for multi-span urban and rural crossings.

How is the Cambridge Flat bridge fabricated?

The Cambridge Flat is fabricated by U.S. Bridge in Cambridge, Ohio as an AISC-certified Advanced Steel Bridge Fabricator. It uses all-bolted, CNC-drilled connections, so no field welding is required during installation.

What is the Cambridge Flat bridge best used for?

The Cambridge Flat is best suited for multi-span urban and rural crossings. Common applications include multi-span river crossings, urban roadway bridges, rural highway spans.

Where is the Cambridge Flat commonly installed?

The Cambridge Flat is installed for projects such as multi-span river crossings, urban roadway bridges, rural highway spans, and other crossings that match its span range and loading.

What span lengths can the Cambridge Flat cover?

A typical Cambridge Flat covers about 60–250 ft. Every bridge is custom-engineered to the site, so the exact span, width, skew and loading are confirmed during design.

Is the Cambridge Flat AASHTO compliant?

Yes. The Cambridge Flat is designed to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer.

What finishes are available for the Cambridge Flat?

The Cambridge Flat is offered in weathering steel or hot-dip galvanized steel, with optional shop-applied paint systems for added durability and custom color.

How is the Cambridge Flat delivered and installed?

The Cambridge Flat is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What type of bridge is the U.S. Bridge Liberty?

The Liberty is a modular panel truss derived from the constant-depth Pratt form, engineered for permanent and rapid or emergency installations.

How is the Liberty bridge fabricated?

The Liberty is fabricated by U.S. Bridge in Cambridge, Ohio as an AISC-certified Advanced Steel Bridge Fabricator. It uses all-bolted, CNC-drilled connections, so no field welding is required during installation.

What is the Liberty bridge best used for?

The Liberty is best suited for permanent and rapid or emergency installations. Common applications include emergency and disaster-response crossings, military and temporary access, permanent rural roadways.

Where is the Liberty commonly installed?

The Liberty is installed for projects such as emergency and disaster-response crossings, military and temporary access, permanent rural roadways, and other crossings that match its span range and loading.

What span lengths can the Liberty cover?

A typical Liberty covers about 40–200 ft. Every bridge is custom-engineered to the site, so the exact span, width, skew and loading are confirmed during design.

Is the Liberty AASHTO compliant?

Yes. The Liberty is designed to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer.

What finishes are available for the Liberty?

The Liberty is offered in weathering steel or hot-dip galvanized steel, with optional shop-applied paint systems for added durability and custom color.

How is the Liberty delivered and installed?

The Liberty is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What type of bridge is the U.S. Bridge Seneca?

The Seneca is a bowstring Pratt truss with a parabolic arched top chord, engineered for signature vehicular and gateway crossings.

How is the Seneca bridge fabricated?

The Seneca is fabricated by U.S. Bridge in Cambridge, Ohio as an AISC-certified Advanced Steel Bridge Fabricator. It uses all-bolted, CNC-drilled connections, so no field welding is required during installation.

What is the Seneca bridge best used for?

The Seneca is best suited for signature vehicular and gateway crossings. Common applications include gateway and signature crossings, park and campus entrances, urban river spans.

Where is the Seneca commonly installed?

The Seneca is installed for projects such as gateway and signature crossings, park and campus entrances, urban river spans, and other crossings that match its span range and loading.

What span lengths can the Seneca cover?

A typical Seneca covers about 80–250 ft. Every bridge is custom-engineered to the site, so the exact span, width, skew and loading are confirmed during design.

Is the Seneca AASHTO compliant?

Yes. The Seneca is designed to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer.

What finishes are available for the Seneca?

The Seneca is offered in weathering steel or hot-dip galvanized steel, with optional shop-applied paint systems for added durability and custom color.

How is the Seneca delivered and installed?

The Seneca is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What type of bridge is the U.S. Bridge Viking?

The Viking is a modified bowstring Pratt truss with vertical end posts, engineered for architectural vehicular crossings.

How is the Viking bridge fabricated?

The Viking is fabricated by U.S. Bridge in Cambridge, Ohio as an AISC-certified Advanced Steel Bridge Fabricator. It uses all-bolted, CNC-drilled connections, so no field welding is required during installation.

What is the Viking bridge best used for?

The Viking is best suited for architectural vehicular crossings. Common applications include architectural roadway crossings, river and canal spans, campus and resort entrances.

Where is the Viking commonly installed?

The Viking is installed for projects such as architectural roadway crossings, river and canal spans, campus and resort entrances, and other crossings that match its span range and loading.

What span lengths can the Viking cover?

A typical Viking covers about 80–250 ft. Every bridge is custom-engineered to the site, so the exact span, width, skew and loading are confirmed during design.

Is the Viking AASHTO compliant?

Yes. The Viking is designed to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer.

What finishes are available for the Viking?

The Viking is offered in weathering steel or hot-dip galvanized steel, with optional shop-applied paint systems for added durability and custom color.

How is the Viking delivered and installed?

The Viking is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What type of bridge is the U.S. Bridge Thru Truss?

The Thru Truss is a high or box through-truss with portal frames, engineered for long-span highway and rail crossings.

How is the Thru Truss bridge fabricated?

The Thru Truss is fabricated by U.S. Bridge in Cambridge, Ohio as an AISC-certified Advanced Steel Bridge Fabricator. It uses all-bolted, CNC-drilled connections, so no field welding is required during installation.

What is the Thru Truss bridge best used for?

The Thru Truss is best suited for long-span highway and rail crossings. Common applications include long-span highway crossings, major river and valley spans, railroad and freight corridors.

Where is the Thru Truss commonly installed?

The Thru Truss is installed for projects such as long-span highway crossings, major river and valley spans, railroad and freight corridors, and other crossings that match its span range and loading.

What span lengths can the Thru Truss cover?

A typical Thru Truss covers about 150–400 ft. Every bridge is custom-engineered to the site, so the exact span, width, skew and loading are confirmed during design.

Is the Thru Truss AASHTO compliant?

Yes. The Thru Truss is designed to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer.

What finishes are available for the Thru Truss?

The Thru Truss is offered in weathering steel or hot-dip galvanized steel, with optional shop-applied paint systems for added durability and custom color.

How is the Thru Truss delivered and installed?

The Thru Truss is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What type of bridge is the U.S. Bridge Cortez?

The Cortez is a simple-span rolled or fabricated steel beam bridge, engineered for short-span replacements and low dead load.

How is the Cortez bridge fabricated?

The Cortez is fabricated by U.S. Bridge in Cambridge, Ohio as an AISC-certified Advanced Steel Bridge Fabricator. It uses all-bolted, CNC-drilled connections, so no field welding is required during installation.

What is the Cortez bridge best used for?

The Cortez is best suited for short-span replacements and low dead load. Common applications include short-span road crossings, bridge and culvert replacements, low-dead-load applications.

Where is the Cortez commonly installed?

The Cortez is installed for projects such as short-span road crossings, bridge and culvert replacements, low-dead-load applications, and other crossings that match its span range and loading.

What span lengths can the Cortez cover?

A typical Cortez covers about Up to 80 ft. Every bridge is custom-engineered to the site, so the exact span, width, skew and loading are confirmed during design.

Is the Cortez AASHTO compliant?

Yes. The Cortez is designed to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer.

What finishes are available for the Cortez?

The Cortez is offered in weathering steel or hot-dip galvanized steel, with optional shop-applied paint systems for added durability and custom color.

How is the Cortez delivered and installed?

The Cortez is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What type of bridge is the U.S. Bridge Voyager?

The Voyager is a constant-depth Pratt truss with parallel chords and vertical end posts, engineered for light vehicular, driveway and recreation use.

How is the Voyager bridge fabricated?

The Voyager is fabricated by U.S. Bridge in Cambridge, Ohio as an AISC-certified Advanced Steel Bridge Fabricator. It uses all-bolted, CNC-drilled connections, so no field welding is required during installation.

What is the Voyager bridge best used for?

The Voyager is best suited for light vehicular, driveway and recreation use. Common applications include private driveways and estates, parks and recreation areas, trail and light-traffic crossings.

Where is the Voyager commonly installed?

The Voyager is installed for projects such as private driveways and estates, parks and recreation areas, trail and light-traffic crossings, and other crossings that match its span range and loading.

What span lengths can the Voyager cover?

A typical Voyager covers about 40–150 ft. Every bridge is custom-engineered to the site, so the exact span, width, skew and loading are confirmed during design.

Is the Voyager AASHTO compliant?

Yes. The Voyager is designed to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer.

What finishes are available for the Voyager?

The Voyager is offered in weathering steel or hot-dip galvanized steel, with optional shop-applied paint systems for added durability and custom color.

How is the Voyager delivered and installed?

The Voyager is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

How do I choose the right U.S. Bridge design?

Start with the application and span. Short crossings with low dead load suit the Cortez; classic vehicular spans suit the Cambridge and Cambridge Flat; architectural or gateway crossings suit the Seneca and Viking; the longest spans use the Thru Truss; light and recreational sites suit the Voyager; and rapid or emergency builds use the modular Liberty. Use the filters above to narrow by application and span, or contact a U.S. Bridge representative for a recommendation.

What is the difference between a Warren truss and a Pratt truss?

A Warren truss (Cambridge and Cambridge Flat) uses a series of equilateral triangles and eliminates vertical members at the top-chord panel points, which is very efficient in steel. A Pratt-based truss (Voyager, Seneca, Viking and Liberty) adds vertical members at every panel point, which shrinks the floor beams and can minimize or eliminate stringers.

Are U.S. Bridge designs AASHTO compliant?

Yes. Every U.S. Bridge design is engineered to current AASHTO standards (HL-93 and HS-20) and stamped by a licensed Professional Engineer. U.S. Bridge is an AISC-certified Advanced Steel Bridge Fabricator.

Can these bridges be customized for my project?

Yes. Span, width, skew, camber, loading, railing, decking and finish are all tailored to your site. U.S. Bridge also engineers pedestrian, railroad and fully custom specialty structures beyond the standard vehicular lineup.

Pedestrian, Railroad & Custom 21

What is a U.S. Bridge pedestrian bridge?

Architectural clear-span pedestrian bridges for trails, parks and campuses, engineered to applicable pedestrian load and accessibility standards while giving you freedom in span, width and style.

How are U.S. Bridge pedestrian bridges fabricated?

U.S. Bridge is an AISC-certified Advanced Steel Bridge Fabricator in Cambridge, Ohio. Structures are engineered by licensed Professional Engineers and fabricated with all-bolted, CNC-drilled connections for fast field assembly.

What are U.S. Bridge pedestrian bridges best used for?

Common applications include parks and recreational trails, university and corporate campuses, residential and mixed-use developments, and similar projects that match the required loading, span and clearances.

Can a pedestrian structure be customized to my site?

Yes. Span, width, geometry, loading, finish and connection details are all tailored to your project and confirmed during engineering.

What design standards do U.S. Bridge pedestrian bridges meet?

They are designed to the AASHTO LRFD Guide Specifications for the Design of Pedestrian Bridges, with slopes, surfaces, clear widths and railing heights engineered to ADA accessibility guidance.

What live load are pedestrian bridges designed for?

A 90 psf pedestrian live load is standard, with optional H-5 or H-10 maintenance-vehicle loading where service access is required.

How is a U.S. Bridge pedestrian structure delivered and installed?

It is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What is a U.S. Bridge railroad bridge?

Heavy-load steel railroad bridges built to AREMA standards for freight, short-line and industrial rail, customized for a wide range of spans, clearances and site conditions.

How are U.S. Bridge railroad bridges fabricated?

U.S. Bridge is an AISC-certified Advanced Steel Bridge Fabricator in Cambridge, Ohio. Structures are engineered by licensed Professional Engineers and fabricated with all-bolted, CNC-drilled connections for fast field assembly.

What are U.S. Bridge railroad bridges best used for?

Common applications include freight rail corridors, short-line and regional railroads, industrial rail spurs, and similar projects that match the required loading, span and clearances.

Can a railroad structure be customized to my site?

Yes. Span, width, geometry, loading, finish and connection details are all tailored to your project and confirmed during engineering.

What standards do U.S. Bridge railroad bridges meet?

They are engineered to the AREMA Manual for Railway Engineering and detailed for the demanding fatigue environment of rail traffic.

What rail live load are railroad bridges designed for?

They are designed for Cooper E-80 heavy freight live load, or the specific loading required by the railroad.

How is a U.S. Bridge railroad structure delivered and installed?

It is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

What counts as a custom U.S. Bridge structure?

When a project does not fit a standard design, U.S. Bridge engineers custom steel structures, from industrial platforms and conveyor supports to launch towers and one-of-a-kind crossings.

Does U.S. Bridge engineer and fabricate custom structures in-house?

U.S. Bridge is an AISC-certified Advanced Steel Bridge Fabricator in Cambridge, Ohio. Structures are engineered by licensed Professional Engineers and fabricated with all-bolted, CNC-drilled connections for fast field assembly.

What are U.S. Bridge custom structures best used for?

Common applications include assembly line and equipment support, conveyor belt and material handling systems, industrial platforms and access structures, and similar projects that match the required loading, span and clearances.

How customized can a specialty structure be?

Yes. Span, width, geometry, loading, finish and connection details are all tailored to your project and confirmed during engineering.

Who engineers and fabricates custom U.S. Bridge structures?

Licensed Professional Engineers design and stamp each structure, and it is built in-house by an AISC-certified Advanced Steel Bridge Fabricator using CNC-drilled, all-bolted connections.

What kinds of geometry can U.S. Bridge fabricate?

Curved, skewed, sloped and multi-level structures can be fabricated to tight tolerance, tailored to your project loads and codes.

How is a U.S. Bridge custom structure delivered and installed?

It is prefabricated in Cambridge, Ohio and shipped as ready-to-assemble, all-bolted components, which keeps field installation fast and predictable.

Flooring & Railing 10

What bridge deck options does U.S. Bridge offer?

U.S. Bridge offers five deck systems: concrete deck slab, corrugated steel bridge plank, nail-laminated timber floor, open grid steel deck, and precast concrete plank.

How do I choose the right bridge deck?

The best deck depends on span, traffic and loading, weight limits, setting and budget. Concrete suits most highway spans, steel plank and open grid reduce dead load, timber suits rustic trails, and precast speeds installation. U.S. Bridge engineers the deck as part of the complete structure.

How thick is a concrete bridge deck slab?

A concrete deck slab is typically designed between 7 and 9 inches thick and reinforced with two layers of steel reinforcing bars, often epoxy-coated for corrosion protection.

What is a stay-in-place (SIP) form?

A stay-in-place form is a permanent light-gauge metal form attached to the steel superstructure that supports the concrete deck pour and remains as part of the structure, reducing field forming.

Does U.S. Bridge supply the decking materials?

Yes. U.S. Bridge supplies the deck materials for each system, including steel planking, SIP forms, and the lumber, nails and clips for timber decks.

What railing types does U.S. Bridge offer?

U.S. Bridge offers five railing and barrier systems: ornamental, concrete safety shape, tubular, W-beam guardrail and thrie-beam guardrail.

What is the difference between W-beam and thrie-beam guardrail?

Both are galvanized steel beam guardrails. W-beam has two corrugations and is the standard vehicular rail; thrie-beam has three corrugations and provides a higher containment level for heavier or higher-speed traffic.

Can railing be customized to match a project aesthetic?

Yes. Ornamental and tubular railings can be customized in pattern, profile and color, and steel railings can receive architectural paint systems over galvanizing.

Are U.S. Bridge vehicular barriers crash-tested?

Yes. Vehicular barriers, including the concrete safety shape and beam guardrails, are available to meet AASHTO MASH and NCHRP 350 crash-test levels as required by the project.

What pedestrian railing height is required?

Pedestrian railings are engineered to meet applicable code heights and opening limits to prevent falls, with ornamental and tubular options for architectural settings.

Bridge Kits 6

What is a U.S. Bridge Bridge Kit?

A Bridge Kit is a DIY steel bridge solution. U.S. Bridge custom-designs and manufactures all the steel, then ships the complete kit to your job site for installation by your own crews.

What is accelerated bridge construction (ABC)?

Accelerated bridge construction is an approach that builds bridges faster and at lower cost while maintaining safety, quality and durability. Bridge Kits support ABC by moving engineering and fabrication off the critical path.

What is included in a Bridge Kit?

Each kit includes the engineering and design, all manufactured steel, hot-dip galvanizing for corrosion protection, and freight to your job site. Every piece and part required for the project is provided.

Who installs a Bridge Kit?

You do. Bridge Kits are designed for builders who have the labor and equipment to install but not the engineering or manufacturing capabilities, so installation is handled by your own crews.

Can a Bridge Kit ship internationally?

Yes. U.S. Bridge ships Bridge Kits to job sites across the United States and worldwide.

How long do Bridge Kits last?

Hot-dip galvanizing provides corrosion protection that keeps the structure durable and largely maintenance-free for 50 to 60 years or more.

Capabilities 15

What engineering services does U.S. Bridge provide?

U.S. Bridge provides complete bridge engineering, from project scoping and preliminary design through final analysis and stamped drawings, including structural member design, code compliance, and verification for vehicular, pedestrian, and specialty bridges.

What codes do U.S. Bridge designs follow?

All bridges are designed to applicable industry standards, including current AASHTO bridge design specifications, and are stamped by a licensed Professional Engineer.

Can U.S. Bridge work with our engineer or contractor?

Yes. Our engineering team collaborates with project owners, contractors, and consulting engineers to develop efficient, buildable solutions that meet structural, site, and budget requirements.

How early should engineering begin on a bridge project?

As early as possible. Involving U.S. Bridge during scoping and preliminary design helps optimize span, geometry, and cost before final engineering begins.

Where are U.S. Bridge components manufactured?

All steel components are fabricated at the U.S. Bridge facility in Cambridge, Ohio.

Are U.S. Bridge bridges galvanized?

Yes. Components can be hot-dip galvanized and coated for long-term corrosion resistance, helping bridges stay durable and low-maintenance for decades.

What is prefabricated, modular construction?

Bridges are fabricated off-site as modular components and shipped ready to assemble, which reduces on-site labor, shortens schedules, and improves safety.

How is manufacturing quality controlled?

Each component is inspected at every stage of fabrication, from material selection to final welding, to meet structural standards, tolerances, and safety requirements before it ships.

What can U.S. Bridge custom-fabricate?

Beyond standard bridges, U.S. Bridge fabricates custom components for bridges, industrial applications, and specialty structures, including intricate connections, non-standard geometry, and heavy-duty reinforcements.

Can custom components integrate with existing structures?

Yes. We engineer each component to align precisely with existing infrastructure, equipment, or mechanical systems, minimizing field modifications.

Is custom fabrication held to the same quality standards?

Yes. Every custom component undergoes the same dimensional checks, welding inspection, and structural verification as our standard bridge systems.

Does U.S. Bridge install the bridge?

U.S. Bridge provides installation support and guidance, including documentation and on-site technical assistance. Installation itself is typically performed by your contractor or field crews.

What installation documentation is provided?

We provide installation manuals, drawings, and guidance covering component placement, connection details, lifting points, and assembly sequences.

Does U.S. Bridge offer on-site support during erection?

Yes. When needed, our team provides on-site technical assistance to help crews interpret drawings, sequence the assembly, and resolve field questions.

What happens after the bridge is assembled?

We can assist with final inspections, alignment checks, and verification that the bridge is installed according to design specifications.

Company 4

When was U.S. Bridge founded?

U.S. Bridge traces its roots to 1936, when it began as The American Culvert Company in Cambridge, Ohio. It became The Ohio Bridge Corporation in 1952 and adopted the U.S. Bridge name in 1987.

Where is U.S. Bridge located?

U.S. Bridge designs and fabricates its steel bridges at its facility at 201 Wheeling Avenue, Cambridge, Ohio.

What certifications does U.S. Bridge hold?

U.S. Bridge is an AISC-certified Advanced Steel Bridge Fabricator with Fracture Critical and Sophisticated Paint System endorsements, and maintains SSPC QP3 painting certification.

Is U.S. Bridge an equal opportunity employer?

Yes. U.S. Bridge is an equal opportunity employer.

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